JP2011100517A - Device and method for reproducing magneto-optic recording medium - Google Patents

Abstract

An apparatus and method for reproducing data of two or more tracks in parallel by incorporating a magneto-optical disk having tracks formed of magnetic thin wires as a data recording area.
A controller for selecting four adjacent tracks on a magneto-optical disk and a current supply for supplying a pulse current to the selected tracks connected to electrodes provided at both ends of the track. And a magnetic transfer film 8 in close contact with the area including the reproduction area 5 _RO fixed to each of all the tracks 5 on the surface of the magneto-optical disk 50, and polarized on the selected track 5 through the magnetic transfer film 8. And a detector that detects the optical rotation angle of the light reflected from the track 5 and reproduces the data recorded on the four tracks 5 in parallel. Thus, the domain wall generated in the track 5 is intermittently moved by the pulse current, and the data of the area that has reached the reproduction area 5 _RO is reproduced when the domain wall is stationary.
[Selection] Figure 3

Description

  The present invention applies a reproducing apparatus for reading data from a magnetic recording medium in a magneto-optical manner, in particular, a magnetic recording medium in which a track is formed of a thin line-shaped magnetic material, and supplies a pulse current to create a magnetic domain in the track. The present invention relates to a magneto-optical recording medium reproducing apparatus and a magneto-optical recording medium reproducing method for reproducing while moving.

  In storage devices such as hard disk drives (HDD), with the increase in the amount of information to be handled, higher recording density and higher speed of recording and reproduction are being promoted. As the recording density increases, the tracks of recording media such as magnetic disks used in HDDs and the like become narrower in pitch. In order to detect the magnetism in such a minute area, the recording / reproducing method is GMR (Giant MagnetoResistance: A magnetic recording system using a magnetic head composed of a giant magnetoresistive element or the like is applied.

  In recording and reproduction on a magnetic disk, the disk is rotated and driven by a spindle motor, and the magnetic head is moved only in the radial direction of the disk, thereby magnetizing (recording) along a track (in the circumferential direction of the disk) in a predetermined direction. ), Or detect (reproduce) magnetism. In order to increase the speed of recording and reproduction in such a disc, firstly, the rotational speed of the disc is increased. However, there is a limit to increasing the rotational speed due to problems such as track magnetization in recording, time required for magnetic detection in reproduction, and malfunction due to disk vibration. For this reason, in a storage device configured by stacking about 2 to 10 magnetic disks such as an HDD built in a personal computer, each magnetic disk is provided with a magnetic head so that each magnetic disk can be recorded or reproduced in parallel. It is possible to do.

US Pat. No. 6,834,005

T. Koyama et al., Appl. Phys. Express 1, 101303 (2008)

  The data that can be reproduced simultaneously by the storage device such as the HDD is limited to the number of built-in disks, and when reproducing a large amount of data at a high speed, it is necessary to operate a plurality of data simultaneously. For example, in order to realize a super high-vision (high-definition television) system, it is necessary to reproduce at a super-high speed of about 72 Gbps. Even in a super high-definition system for experiments of about 24 Gbps, it is necessary to operate dozens of large-capacity storages for servers equipped with, for example, about 3 to 10 disks at the same time. I need.

  In order to reproduce at a higher speed with one storage device, it is necessary to reproduce two or more data from one disk at the same time, and as a method therefor, there is a method of providing a plurality of magnetic heads in the radial direction of the disk. . However, since the circumference, that is, the track length, is different between the outside and inside of the disk, when the disk is driven to rotate, the moving speed of the magnetic head on the track differs, and the track near the outer periphery of the disk has a length corresponding to one data. It is necessary to adjust the position on the disk so as to lengthen the length. Alternatively, the length difference is slight if it is reproduced simultaneously between two to a dozen or more adjacent tracks, but in this case as well, there is a possibility that a discrepancy occurs in the length of one rotation of the disc. It is necessary to finely adjust the position of each magnetic head. Furthermore, in order to simultaneously reproduce two or more tracks, a magnetic head requires TMR elements and the like for the number of tracks to be reproduced and wirings connected to them to supply current, but they are insulated from each other. Thus, it is difficult to face each of two or more adjacent tracks at a narrow pitch.

  Here, as a method of moving the recording or reproducing area without driving the recording medium, Patent Document 1 discloses that a track is formed by forming a thin line-shaped magnetic body (hereinafter appropriately magnetic thin line) into a U-shape or the like. A memory device is disclosed. This is based on the characteristic that when a magnetic material is formed in a thin line shape, magnetic domains are formed in the length direction, and when a current is further supplied in the length direction, the domain walls that delimit the magnetic domains shift and move (non- Patent Document 1). That is, each of the recording and reproducing magnetic heads is fixed at a predetermined position (a U-shaped top portion in Patent Document 1) on the track (magnetic wire), and a current is reversibly supplied from both ends to obtain a desired one. Is moved to a position facing the head. In this method, although it varies depending on the shape of the magnetic material (line width, etc.) and the current to be supplied, the moving speed of the domain wall is extremely high, from several tens m / s to about 100 m / s. Expected to exceed playback speed.

  In Patent Document 1, in order to enable rewriting of data by a random access method, wave-shaped magnetic wires in which a large number of U-shapes are connected in series are further provided in parallel, and a magnetic head is provided at each of the U-shaped top portions. However, it is necessary to form the magnetic wire in three dimensions, and the structure of the recording medium becomes complicated. For example, in the case of a reproduction-only recording medium on which information consisting of continuous data such as a movie is recorded, reproduction is started from the top data (magnetic domain), and the movement of the magnetic domain may be unidirectional and at a constant speed. Therefore, the inventors of the present application have formed magnetic thin wires concentrically, and used this as a track in the same manner as a general magnetic disk or magneto-optical disk to form a disk-shaped recording medium (disk). With such a recording medium, it is not necessary to rotate the recording medium body, so there is no malfunction due to vibration, etc. Also, by supplying current to each track, the movement of each data (magnetic domain) for multiple tracks Therefore, it is possible to reproduce a plurality of tracks at the same time without shifting data between the tracks.

  The present invention has been devised in view of the above problems in reproduction, and provides a method and apparatus for reproducing two or more pieces of data in parallel from one recording medium for the recording medium in which a track is formed by the magnetic thin wire. The purpose is to do.

  In order to solve the above-mentioned problems, the present inventor adopts a magneto-optical method applied to a magneto-optical (MO) disk as a method of reproducing data from adjacent tracks having a narrow pitch. did. In the magneto-optical reproduction method, the recording layer of a magnetic track is irradiated with laser light, and when the light is reflected, the polarization plane rotates (rotates), and the recording layer is magnetized. It utilizes the fact that the direction of optical rotation is reversed due to the difference in direction. However, since the optical rotation angle (Kerr rotation angle) by the magnetic material applied to the recording layer is approximately less than 1 °, in order to increase detection accuracy and enable simultaneous detection from a plurality of minute magnetic domains, A method using a magnetic transfer film having a large magneto-optical effect has been reached.

  A magneto-optical recording medium reproducing apparatus according to the present invention includes a plurality of magnetic thin wires formed by forming magnetic bodies on a substrate in a thin line shape as a data recording area, and binary data is stored in each of the magnetic thin wires. A magneto-optical recording medium continuously recorded in the direction of the fine magnetic wire as either one of two different directions of magnetization is incorporated, and two or more magnetic fine wires are selected and the data recorded on each is paralleled. It is a device for playback. In order to enable such reproduction, the magneto-optical recording medium reproducing apparatus uses a magnetic transfer film in which the magnetization direction changes in accordance with the magnetization direction of the magnetic wire in the closely contacted area, on the surface of the magneto-optical recording medium. Are provided in close contact with a region including a magneto-optical detection region, the position of which is set in advance for each of the plurality of magnetic thin wires. The magneto-optical recording medium reproducing apparatus further includes control means for selecting two or more adjacent magnetic thin wires from the plurality of magnetic thin wires of the magneto-optical recording medium, and both ends of each of the plurality of magnetic thin wires of the magneto-optical recording medium. Connected to the two or more magnetic thin wires, the domain wall generated between the region where one of the binary data is recorded and the region where the other binary data is recorded in the magnetic thin wire is intermittently connected. Current supply means for supplying a pulse current to be moved in the direction of the thin line, and polarization in one direction in each of the two or more magnetic thin lines of the magneto-optical recording medium through the magnetic transfer film Irradiating means for injecting the light, and detecting the direction of polarization of the light incident from the irradiating means and reflected from the two or more magnetic thin wires of the magneto-optical recording medium and transmitted through the magnetic transfer film. From the direction of polarization Detecting means for reproducing data recorded on each of the two or more magnetic thin wires in parallel, the detecting means intermittently connecting the domain walls in the magnetic thin wires in synchronization with a pulse current supplied by the current supplying means. The data that has reached the magneto-optical detection area of the magnetic wire is reproduced when the moving object is stationary.

  With this configuration, the magneto-optical recording medium reproducing apparatus supplies a pulse current to the area in which one of binary data is recorded in the direction of the fine line in the magnetic fine line of the magneto-optical recording medium by the distance of this area. Since the data in the magneto-optical detection area, which is a fixed area for data reproduction, is moved in order, the magneto-optical recording medium main body is fixed at high speed without using a rotational drive means such as a spindle motor. Data can be moved. In addition, since the magneto-optical recording medium reproducing apparatus can control the moving speed of the area where data is recorded in the magnetic thin wire for each magnetic thin wire by supplying current, it can move the data of two or more magnetic thin wires in parallel without malfunction. Further, in the magneto-optical recording medium reproducing apparatus, the magnetic transfer film is brought into close contact with the magneto-optical detection region of the magnetic thin line of the magneto-optical recording medium, so that the light reflected from the magnetic thin line is rotated by passing through the magnetic transfer film. Thus, the change in the direction of polarization is increased to improve the magnetic detection accuracy by the magneto-optical method, and each data of two or more magnetic wires adjacent at a narrow pitch can be detected from a common reflected light.

  In the magneto-optical recording medium reproducing apparatus, the detection means includes a polarizer that blocks light having a specific direction in the light reflected from the two or more magnetic wires of the magneto-optical recording medium and transmitted through the magnetic transfer film. An image pickup device that picks up the light transmitted through the polarizer at a stationary time in the intermittent movement of the domain wall in the magnetic thin wire, and adjusts the area imaged by the image pickup device to each of the two or more magnetic thin wires. Thus, the brightness of light can be reproduced as 0 or 1 data. With this configuration, the magneto-optical recording medium reproducing apparatus can reproduce two or more data in parallel by applying a conventionally known imaging apparatus.

  Further, it is preferable that the magneto-optical recording medium has a shape in which a plurality of magnetic thin wires are concentrically formed on a disk-shaped substrate, and each of the magnetic thin wires lacks a part of a ring. With this configuration, the magneto-optical recording medium has the same outer shape as a conventionally known recording medium, and even when the size of the magneto-optical recording medium is limited, the magneto-optical recording medium has a long and continuous shape on the substrate without bending the magnetic wire. Therefore, it is not necessary to increase the size of the magneto-optical recording medium reproducing apparatus.

  Further, it is preferable that the magneto-optical recording medium has a constricted portion formed in the magnetic thin wire in the vicinity of the magnetic detection region. With this configuration, it is possible to make it difficult to cause a problem such as a data shift between the magnetic thin wires reproduced in parallel.

  The magnetic transfer film is preferably made of bismuth-substituted magnetic garnet. With this configuration, the reflected light of the magneto-optical recording medium is further rotated in the direction of polarization to increase the cumulative rotation angle, thereby further improving the detection accuracy.

  Also, in the magneto-optical recording medium reproducing method according to the present invention, two or more magnetic thin wires are selected for a magneto-optical recording medium having a plurality of magnetic thin wires formed by forming the magnetic material in a thin line shape as a data recording area. Thus, the data recorded in each is reproduced in parallel. To this end, the magneto-optical recording medium reproducing method starts with a magnetic fine wire in a region that is in close contact with a predetermined region including a magneto-optical detection region positioned at each of a plurality of magnetic fine wires on the surface of the magneto-optical recording medium. A selection step of selecting two or more adjacent magnetic thin wires from a plurality of magnetic thin wires of the magneto-optical recording medium, and performing a preparatory step of closely adhering a magnetic transfer film whose magnetization direction changes corresponding to the magnetization direction of And a reproducing step of reproducing data recorded on each of the two or more magnetic thin wires of the magneto-optical recording medium in parallel. In the reproducing step, a domain wall generated between the area where one of the binary data is recorded and the area where the other binary data is recorded in the two or more magnetic thin lines. A current supply process for supplying a pulse current to be intermittently moved in the direction of the thin line and a magnetic transfer film that is transmitted through the magnetic transfer film so that one is provided in each magneto-optical detection region of the two or more magnetic thin lines of the magneto-optical recording medium. Light for detecting the direction of polarization of light that has been incident on the two or more magnetic thin lines of the magneto-optical recording medium and transmitted through the magnetic transfer film. From the detection process and the direction of the polarization detected in the light detection process, in synchronization with the pulse current supplied in the current supply process, the magnetic thin wire Magneto-optical inspection And performing the data reproduction process for reproducing data which has reached the region.

  By such a procedure, two or more data can be accurately reproduced simultaneously on a magneto-optical recording medium having a narrow pitch track made of a fine line-shaped magnetic material.

  According to the magneto-optical recording medium reproducing apparatus of the present invention, data can be reproduced simultaneously from two or more adjacent tracks even in a narrow-pitch track, so that information composed of high-density data such as high-definition images is reproduced. The apparatus which performs can be comprised compactly. Also, according to the magneto-optical recording medium reproducing method according to the present invention, information composed of high-density data such as the high-definition image can be reproduced appropriately.

1 is a perspective view schematically showing a configuration of a magneto-optical recording medium reproducing apparatus according to an embodiment of the present invention. 1 is a plan view schematically illustrating a configuration of a magneto-optical recording medium built in a magneto-optical recording medium reproducing apparatus according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of a reproducing area of a magneto-optical recording medium for explaining a reproducing method by the magneto-optical recording medium reproducing apparatus shown in FIG. It is sectional drawing of the length direction explaining typically the movement of the magnetic domain in the magnetic fine wire of the magneto-optical recording medium shown in FIG. FIG. 3 is an enlarged plan view of a reproduction area of the magneto-optical recording medium shown in FIG. FIG. 2 is an enlarged view of a reproducing area of the magneto-optical recording medium reproducing device and the magneto-optical recording medium shown in FIG. 1. 3 is a flowchart showing a magneto-optical recording medium reproducing method according to an embodiment of the present invention.

  Hereinafter, embodiments for realizing a magneto-optical recording medium reproducing apparatus and a magneto-optical recording medium reproducing method according to the present invention (hereinafter, appropriately reproducing apparatus and reproducing method) will be described with reference to the drawings.

[Magnetic recording medium playback device]
As shown in FIG. 1, a reproducing apparatus (a magneto-optical recording medium reproducing apparatus) 1 according to an embodiment of the present invention incorporates a magneto-optical disk (magneto-optical recording medium) 50 and has a predetermined surface (upper surface). The magnetic transfer film 8 attached to the region, the optical system (irradiation means) 10 that irradiates the magneto-optical disk 50 through the magnetic transfer film 8 and the incident light reflected by the magneto-optical disk 50. A detection unit (detection unit) 20 that detects incident light, a current supply unit (current supply unit) 30 that supplies a pulse current to the track (magnetic thin wire) 5 (see FIG. 2) of the magneto-optical disk 50, and these are controlled. And a control unit 40. The reproducing apparatus 1 makes light incident on the track 5 formed on the upper surface of the magneto-optical disk 50 in the same manner as the reproduction of the current magneto-optical disk, and this light depends on the magnetization direction of the track 5 by the magneto-optic effect. Data is reproduced by detecting magnetism from the direction of polarization of light reflected by changing the direction of polarization (rotating). In the reproducing apparatus 1, the magneto-optical disk 50 may be replaceable like a current DVD (Digital Versatile Disc) reproducing apparatus, or may be non-replaceable like the current HDD apparatus. In this specification, the surface of the magneto-optical disk 50 is the upper surface that is the light incident / emission surface, and the upper side is the light incident / emission direction.

  The optical system 10 includes a laser irradiation device 11, a lens optically connected to the lens to reduce (or enlarge) the laser beam to a predetermined spot diameter, a lens that converts the reduced laser beam into parallel light, and a laser. The light is composed of an incident polarization filter 13 that uses light of one polarization component (hereinafter, this light is appropriately referred to as polarization). On the other hand, the detection unit 20 includes an output polarization filter (polarizer) 23 that shields polarized light in a specific direction from light reflected and output from the magneto-optical disk 50, and an imaging device 21 that captures the light transmitted through the filter. Is done. The optical system 10 and the detection unit 20 further include movable mirrors 12 and 22, respectively, and move a light incident region (laser spot) on the surface of the magneto-optical disk 50 in the radial direction. The laser irradiation device 11 is a device that irradiates a laser beam having a predetermined wavelength (for example, 500 nm), and a device similar to that applied to a current magneto-optical disk recording / reproducing device can be applied. The imaging device 21 can detect light that has passed through the output polarization filter 23 such as a CCD camera or a photodiode, has a resolution that is less than the track width (planar size of the magnetic domain), and a time resolution that is faster than the reproduction speed of one data. Any photodetector can be used. Further, a lens (not shown) that expands the light in accordance with the resolution of the imaging device 21 may be provided. A known polarizing plate can be applied to the polarizing filters 13 and 23. Further, in each of the optical system 10 and the detection unit 20, the arrangement order of the polarization filters 13, 23, the mirrors 12, 22 and various lenses is not limited to the above, and may be changed.

  The current supply unit 30 is connected to electrodes 52 and 53 (see FIG. 2) provided at both ends of each magnetic wire (track) 5 of the magneto-optical disk 50, and a pulse current is supplied to the magnetic wire 5 in its length direction. Supply. By this pulse current, as will be described later, the area where data is recorded moves intermittently in the magnetic wire 5 along the length direction of the magnetic wire 5. That is, in the reproducing apparatus and reproducing method according to the present invention, the magneto-optical disk 50 is not driven by itself. The control unit 40 selects the magnetic thin wire 5 for reproducing data, instructs the magnetic thin wire 5 to supply current to the current supply unit 30 according to the selected magnetic thin wire 5, and moves the mirrors 12 and 22 of the optical system 10 and the detection unit 20. Further, the detection unit 20 reproduces data in accordance with the cycle of the pulse current supplied by the current supply unit 30.

(Magnetic disk)
A magneto-optical disk (magneto-optical recording medium) 50 storing data to be reproduced by the reproducing apparatus 1 according to an embodiment of the present invention is the same as a current magnetic disk or magneto-optical disk as shown in FIG. A plurality of fine magnetic wires 5, 5,... Are concentrically formed on the surface (upper surface) as a data recording (storage) area on the basis of the disk-shaped substrate 7. For each magnetic thin wire 5, binary data, that is, “0” or “1” data is applied to one direction of magnetization or its data every predetermined unit length (data length) in the length direction (thin wire direction). It is recorded as a magnetic domain of magnetization in the opposite direction. Thus, in the present embodiment, the magneto-optical recording medium 50 is called a magneto-optical disk 50 because its outer shape is a disk shape like the current magneto-optical disk and the like, and each of the magnetic thin wires 5 is Since it is similar to the shape of a track which is a data recording area of the magnetic disk or magneto-optical disk, it is appropriately referred to as a track 5. Furthermore, a unit area in which one piece of data of the magnetic wire 5 is stored is referred to as a data area. In the present invention, the magneto-optical disk (magneto-optical recording medium) 50 is configured as follows in order to move the data area in the magnetic wire 5 as described above.

  In the magneto-optical disk 50, each of the magnetic thin wires (tracks) 5 has a C-shape with a part of an annular ring removed in plan view as shown in FIG. 2, and a pair of electrodes 52 and 53 are connected to both ends thereof. Then, as shown in FIG. 3, the insulating layer 6 is formed on the disk-shaped substrate 7. The number of the magnetic thin wires 5 formed on the magneto-optical disk 50 is not particularly limited, and may be set according to the track pitch (width and interval), the size of the magneto-optical disk 50, and the like. In FIG. 3, the magnetic thin wire 5 is indicated by a blank (transparent) region because the magnetization direction is indicated by an arrow inside.

  The magnetic thin wire (track) 5 of the magneto-optical disk 50 is made of a ferromagnetic material, and in particular has a magnetization in a direction perpendicular to the film surface, that is, a perpendicular magnetic anisotropic material, specifically Ni, Fe, Co, etc. Transition metal, alloys thereof, and laminated films of Pd, Pt, and Cu. The thickness (film thickness) of the magnetic wire 5 is preferably 5 to 100 nm, the width (the length in the radial direction of the magneto-optical disk 50) is preferably 100 to 800 nm, and the space between the magnetic wires 5 and 5 is preferably 100 to 800 nm. As the so-called track pitch is narrower, the recording capacity of the magneto-optical disk 50 can be increased. However, the track pitch (the sum of the width and interval of the magnetic wires 5) is set to be equal to or greater than a half wavelength of the laser light emitted from the laser irradiation device 11. The length in the length direction (track length) of the magnetic wire 5 is not particularly limited as long as it is sufficiently longer than the thickness and the length in the width direction. Further, all the magnetic thin wires 5 in the magneto-optical disk 50 do not have to have the same length, but a predetermined number of adjacent magnetic thin wires 5 for reproducing data (detecting magnetism) at the same time (hereinafter referred to as magnetism for appropriate parallel reproduction). The thin wires 5) preferably have the same length. The thin wire shape (planar shape) of the magnetic wire 5 is a straight line that does not bend, or a curve that is sufficiently gentle with respect to the thickness and the length in the width direction, and has a disk shape as in this embodiment. In the case of the magnetic disk (magneto-optical recording medium) 50, it is possible to make it sufficiently long with respect to its outer dimensions, and a ring (arc) is preferable as a shape that can be easily manufactured. Such a magnetic wire 5 can be made longer as it is formed closer to the outer periphery of the magneto-optical disk 50, and the recording area can be enlarged as a whole of the magneto-optical disk 50, so that the same as described above. There is no need to unify the length. The magneto-optical recording medium 50 is not limited to a disk shape, and may be a plate having a rectangular shape in plan view. In this case, the magnetic thin wires 5 may be formed in parallel straight lines.

  The electrodes 52 and 53 of the magnetic wire 5 are made of a general electrode metal material such as a metal such as Cu, Al, Au, Pt, or Ag, or an alloy thereof. In FIG. The magnetic thin wires 5 are stacked on the magnetic wires 5 but may be connected in parallel at both ends of the magnetic thin wires 5 to be reproduced in parallel. In addition, the electrodes 52 and 53 may be formed on the back surface (lower surface). In that case, a part of the substrate 7 is removed so that it can be electrically connected to the current supply unit 30, and FIG. The current supply unit 30 is connected to the lower surface of the magneto-optical disk 50.

A reproduction area (a magneto-optical detection area) 5 _RO is an area for detecting the magnetism of the magnetic wire 5 by the magneto-optic effect, and has a length included in one data area in the magnetic wire 5. The position of the reproduction area 5 _RO is set in advance in the magnetic thin line 5 (the magneto-optical disk 50), and the reproduction area 5 _RO in the adjacent magnetic thin lines 5 and 5 in all the tracks (magnetic thin lines) 5 of the magneto-optical disk 50. , 5 _RO are provided close to each other. This is because one reproduction beam 50 _RO (see FIGS. 5 and 6) is used for each reproduction region 5 _RO of two or more (a predetermined number of magnetic thin lines) selected magnetic wires 5 as one parallel reproduction region 50 _RO (incident light). ) For reproduction. Further, when the reproduction of the predetermined number of tracks 5 is completed (seek) after the completion of the reproduction of the predetermined number of tracks 5 at one time, the distance for moving the laser spot can be minimized. In this embodiment, as shown in FIG. 2, the reproduction area 5 _RO is provided along a straight line of the radius of the magneto-optical disk 50. However, the present invention is not limited to this, and a single straight line deviating from the radius of the magneto-optical disk 50 is provided. Or you may provide along a curve. In the present embodiment, the reproduction region 5 _RO is aligned near the center of the magnetic thin wire 5 in the length direction. However, the present invention is not limited to this, for example, the electrode 52 side that is the leading side of continuous data (see FIG. 4). ). In the reproducing apparatus 1 according to the present embodiment, since the magnetic domain (data area) moves in the magnetic wire (track) 5, as will be described later, the data area in the reproducing area 5 _RO is switched in order.

Such a magneto-optical disk 50 can be manufactured, for example, by forming magnetic thin wires (tracks) 5 by a damascene method as shown below. First, an insulating film such as SiO ₂ or Al ₂ O ₃ is formed on a substrate 7 made of a known substrate material such as a Si substrate or a glass substrate whose surface is thermally oxidized by a known method such as a sputtering method. The insulating film 6 is formed by forming grooves in the shape of magnetic thin wires 5, 5,... By etching such as electron beam lithography and ion milling or reactive ion etching (RIE). A magnetic material is deposited on the insulating layer 6 in a groove by a film forming method such as a sputtering method, and then the magnetic material other than the groove is removed by CMP (Chemical Mechanical Polishing) or the like on the surface. Magnetic thin wires 5, 5,. Then, on both ends of the magnetic wire 5, an electrode metal material is formed by sputtering or the like, processed by photolithography and etching, or lift-off method or the like to form electrodes 52 and 53. Finally, the surface is covered with a resin or the like except for the electrodes 52 and 53 and the reproduction region 5 _RO . Alternatively, the magnetic fine wire 5 may be formed by a lift-off method after forming the underlying insulating film (insulating layer 6), and then the insulating layer 6 may be deposited between the magnetic fine wires 5 and 5. Further, the magneto-optical disk 50 is attached with the magnetic transfer film 8 described later in close contact with the surface including the reproducing region 5 _RO (the surface of the magnetic wire 5) as necessary.

(Magnetic transfer film)
The magnetic transfer film 8 is used for reproducing the magneto-optical disk 50 by the reproducing apparatus 1 according to the embodiment of the present invention. Since the magnetic transfer film 8 is magnetized corresponding to the magnetization of the magnetic material in contact therewith, when it is brought into close contact with the surface of the magneto-optical disk 50, it exhibits magnetization corresponding to the magnetization of the region of the magnetic wire 5 immediately below it. In the case of a magnetic thin wire (track) 5 having perpendicular magnetic anisotropy, as shown in FIG. 3, the magnetic transfer film 8 has an n-th track whose magnetization is upward in the respective reproduction regions 5 _RO , n + 2 and The magnetization of the reproducing region 5 _RO of the magnetic wire 5 is such that the magnetization is upward in the region immediately above the n + 3th track and the magnetization is downward in the region immediately above the n + 1th track in the downward direction. Transcribed. Further, if the magnetic domain immediately below the magnetic transfer film 8 in the magnetic thin wire 5, that is, the magnetic domain in the reproduction region 5 _RO moves and is replaced with a magnetic domain having a different magnetization direction, the magnetization transferred to the magnetic transfer film 8 correspondingly changes. Change quickly.

With respect to the light incident on the magneto-optical disk 50, the angle of rotation of the reflected light is as small as less than 1 ° only at the Kerr rotation angle reflected from the magnetic wire 5, the thickness of the magnetic wire 5 is small, and the light passes through the magnetic wire 5. When the light is reflected from the bottom surface, the optical rotation is performed at the Faraday rotation angle, so that the optical rotation angle is further reduced in proportion to the film thickness. Therefore, in the reproducing apparatus 1 according to the present embodiment, by passing through the magnetic transfer film 8, the difference in the polarization direction of the emitted light due to the difference in the magnetization direction is expanded, thereby improving the magnetic detection accuracy. Accordingly, the magnetic transfer film 8 is preferably made of a material having a large magneto-optical effect (a large Faraday rotation angle) and a high transmittance. Specific examples of such a material include a magnetic garnet film having a low coercive force, and a Gd-Co-based, Gd-Fe-based, and Tb-Fe-based amorphous magnetic film whose compensation temperature is sufficiently higher than the operating temperature. Bismuth-substituted magnetic garnet (Y _3−X Bi _x Fe ₅ O ₁₂ ) having a Faraday rotation angle of about 5 ° / μm (wavelength of 532 nm) is particularly preferable. Bismuth-substituted magnetic garnet can be produced by, for example, forming a film on a Gd ₃ Ga ₅ O ₁₂ (gadolinium gallium garnet: GGG) single crystal substrate by liquid phase epitaxial growth. Affixed and adhered to the surface of the magneto-optical disk 50 (GGG substrate (not shown) is positioned above). As shown in FIG. 2, the magnetic transfer film 8 is attached to and closely adhered to the region including the reproduction region 5 _RO of at least all the magnetic wires 5 on the surface of the magneto-optical disk 50. May be affixed to the surface of the reproducing apparatus 1 or may be brought into close contact with the reproducing apparatus 1 when the magneto-optical disk 50 is built therein.

[Reproduction method by magneto-optical recording medium reproduction apparatus]
Next, a method for reproducing a magneto-optical disk by the magneto-optical recording medium reproducing apparatus according to the present invention will be described. In the present embodiment, the description will be made assuming that the four tracks (magnetic thin wires) adjacent to the nth to n + 3th are reproduced simultaneously. In the regeneration method according to the embodiment of the present invention, as shown in FIG. 7, after performing the preparation step S0, the selection step S1 and the regeneration step S2 are repeated as necessary.

(Preparation process)
The preparation step S0 is a step in which the magneto-optical disk 50 is placed on the stage (not shown) and built in the reproducing apparatus 1, and all cases where the magnetic transfer film 8 is not attached to the magneto-optical disk 50 are all performed. The magnetic transfer film 8 is brought into close contact with the reproduction region 5 _RO of the magnetic wire 5. Further, the output terminals (not shown) of the current supply unit 30 are connected to the electrodes 52 and 53 of all the magnetic wires 5 of the magneto-optical disk 50. In the reproducing apparatus 1, the connection of the magnetic transfer film 8 and the current supply unit 30 to the magneto-optical disk 50 is completed, for example, the reproducing apparatus 1 has the same structure as that of the current non-exchangeable HDD apparatus. If there is, the preparation step S0 is unnecessary, and the process starts from the selection step S1 of the next step.

(Selection process)
In the selection step S1, the control unit 40 stores a predetermined number (2) of data stored in the next reproduction step S2 from the tracks (magnetic thin wires) 5, 5,. The number of tracks 5 is selected. In the present embodiment, four tracks 5 are selected. If the track 5 to be selected is, for example, the first selection step S1 (the selection step S1 next to the preparation step S0), the first to fourth tracks 5 from the outermost periphery of the magneto-optical disk 50 are selected. If it is the second time or later, it may be set to select the next four adjacent tracks adjacent to the four tracks 5 reproduced in the immediately preceding reproduction step S2 (see below). Alternatively, it may be set such that four adjacent tracks 5 can be selected by an operation from the outside of the playback apparatus 1. In the present embodiment, the nth to n + 3th tracks 5 are selected as described above. When the four tracks 5 are selected in the selection step S1, the control unit 40 moves the mirror 12 of the optical system 10 to move the laser spot to the reproduction area 5 _RO (parallel reproduction area 50 _RO ) of the four tracks 5. , And the mirror 22 of the detection unit 20 is moved so that the reflected light from the parallel reproduction region 50 _RO is incident on the imaging device 21. Further, the control unit 40 causes the current supply unit 30 to start supplying the pulse current to the four tracks 5, and the reproduction step S2 is started.

(Regeneration process)
In the reproduction step S2, a pulse current is supplied from the current supply unit 30 to the nth to n + 3th four tracks (magnetic thin wires) 5 of the magneto-optical disk 50 selected in the selection step S1, and the data area is intermittently generated. (Current supply process S21), the reproduction area 5 _RO of these tracks 5 is irradiated (irradiation process S22), the direction of polarization of the reflected light is detected (light detection process S23), and the data area becomes stationary. This is a step of detecting magnetism in the reproduction area 5 _RO of the track 5 at the timing (data reproduction processing S24) (see FIG. 7). Hereinafter, a data area moving method and a magnetic detection method will be described.

(Regeneration process: current supply processing)
First, the movement of the data area in the track (magnetic wire) 5 of the magneto-optical disk 50 will be described with reference to FIG.
In the present embodiment, the magnetic wire 5 is made of a perpendicular magnetic anisotropic material, and its magnetization direction indicates up or down. Therefore, data “0” is downward magnetization, and “1” is upward magnetization. It is assumed that the data is recorded in a data area having a predetermined unit length (data length). The data “0” and “1” recorded on the magnetic wire 5 is referred to as stored data. Here, as shown in FIG. 4A, for one magnetic thin wire 5, four consecutive stored data from the mth data area (data area m) existing in the reproduction area 5 _RO are as follows: An area where “1001” is recorded will be described. Since the data areas m to m + 3 in the magnetic thin wire 5 have the magnetization directions of up, down, down, and up, they correspond to the magnetic domain D1 corresponding to the data area m, and two consecutive data areas of the data area m + 1 and the data area m + 2. Three magnetic domains, ie, a magnetic domain D2 and a magnetic domain D3 corresponding to the data area m + 3, are formed. The data length is preferably 100 to 500 nm although it depends on the width and thickness of the magnetic wire 5. The shorter the data length, the larger the recording capacity of the magneto-optical disk 50, and the faster the reproduction speed of one track (magnetic wire) 5. can do. The data length may be different for each magnetic wire 5, but the same length is used for a predetermined number (four in this embodiment) of magnetic wires 5 that are reproduced in parallel in one reproduction step S <b> 2. It is preferable.

  Domain walls DW1 and DW2 are generated between the magnetic domains D1 and D2 (between the data areas m and m + 1) and between the magnetic domains D2 and D3 (between the data areas m + 2 and m + 3) of the magnetic thin wire 5, respectively. That is, in the magnetic wire 5, a domain wall is generated between an area where data “0” is recorded and an area where data “1” is recorded. In the domain wall DW1, the magnetization gradually changes or rotates from the magnetization direction (upward direction) of the magnetic domain D1 to the magnetization direction (downward direction) of the magnetic domain D2, and the magnetization also rotates in the domain wall DW2. The length of the domain walls DW1 and DW2 (length in the length direction of the magnetic wire 5) is about 5 to 100 nm, although it depends on the width and thickness of the magnetic wire 5 and the data length.

In FIG. 4A, since there is a magnetic domain D1 in the reproduction area 5 _RO of the magnetic thin wire 5, upward magnetization is detected, and the stored data “1” in the data area m becomes reproduction data. Details of the magnetization detection method will be described later. As shown in FIG. 4B, a current of a predetermined magnitude is supplied to the magnetic thin wire 5 from the electrodes 52 and 53 at both ends thereof to inject electrons in the right direction. Then, the domain walls DW1 and DW2 move to the right, respectively, affected by the electron spin torque. Then, by supplying the time t _H current to the magnetic domain wall DW1, DW2 is moved the distance of one data length, stopping the supply of electric current, as shown in FIG. 4 (c), playback area 5 of the magnetic wire 5 _Since the magnetic domain D2 has moved to _RO , downward magnetization is detected, and “0” in the data area m + 1 becomes reproduction data. When the current tH is supplied again to the magnetic thin wire 5 for the time t _H and the domain walls DW1 and DW2 are further moved to the right by one data length to stop the current supply, the magnetic domain D2 has two data lengths in the data areas m + 1 and m + 2. Therefore, as shown in FIG. 4D, the magnetic domain D2 is continuously arranged in the reproduction region 5 _RO of the magnetic wire 5 so that the downward magnetization is detected, and “0” in the data region m + 2 is reproduced. It becomes data. Further, when a current t _{H is further} supplied to the magnetic wire 5 for a time t _H , the magnetic domain D3 moves to the reproduction region 5 _RO of the magnetic wire 5 so that upward magnetization is detected and “1” in the data region m + 3 is reproduced. Data (not shown).

In this way, by repeatedly supplying and stopping the current to the magnetic wire 5 for a predetermined time, the domain wall, that is, the magnetic domains on both sides thereof can be moved by a certain distance to be stationary. That is, by adjusting the pulse width (current supply time t _H ) and supplying the pulse current, the data area in the track (magnetic wire) 5 is shifted in the length direction by one data length and fixed in the reproduction area 5. The data area of _RO can be changed in order. Alternatively, in order to move the data area by one data length, it is not limited to supplying current once for a time of the pulse width t _H , but it is moved intermittently with a current supply of a predetermined number of times twice or more, that is, with the current stopped. You may let them. Note that the current stop time t _L in the pulse current may be set to be equal to or greater than the time required for magnetism detection described later, that is, equal to or greater than the time resolution of the imaging device 21. The magnitude of the current is increased based on the width and thickness of the magnetic wire 5 and the reproduction speed, since the domain wall moving speed increases as the current density per cross-sectional area of the magnetic wire 5 is increased. In order to supply current in the opposite fixed direction, either positive or negative direct current is used. Specifically, it is preferable to adjust the current density within a range of 10 ⁵ to 10 ¹³ A / m ² , a pulse width t _{H of 1} ps to 10 μs, and a stop time t _{L of} 10 ps to 10 μs.

Furthermore, in the data reproduction by the magneto-optical recording medium reproducing apparatus according to the present invention, since two or more tracks 5 are reproduced in parallel, the data areas of these tracks 5 are moved by one data length. There is a need. The moving distance of the data area is controlled by adjusting the pulse width (t _H ) and the magnitude (current density) of the current. If there is a minute error in the data length or moving distance of each track 5, this is accumulated. There is a risk of shifting by one data length or more. In addition, when a magnetic thin wire (magnetic material) is partially peeled or has surface flaws in its production, a domain wall is likely to be generated and fixed at this portion. There is a risk that the boundary of the data area will be stationary. It is difficult to correct such an error only by supplying a pulse current from the current supply unit 30. Therefore, in the reproducing apparatus according to the present invention, the magneto-optical disk is preferably configured as follows.

If there are constricted or bent portions with a small cross-sectional area (surface perpendicular to the length direction) in addition to the above-mentioned ridges, etc., the magnetic thin wire is likely to generate and fix a domain wall at these locations (patented) Reference 1 and non-patent reference 1). Therefore, in the magneto-optical disk 50, the magnetic wire 5 is preferably formed a constricted portion 54 in the reproducing area 5 _RO vicinity. In the present embodiment, as shown in FIG. 5, the reproducing area 5 _RO of the magnetic wire (track) 5 (shown as a parallel reproducing area 50 _{RO in} FIG. 5) is behind (front side) in the domain wall movement direction (data area movement direction). ) Is formed with a constricted portion 54. By forming the magnetic thin wire 5 in such a shape, the domain wall that is separated from the constricted portion 54 and exists in the vicinity in a state where the supply of current is stopped is fixed after moving to the constricted portion 54 ( Trapped). In FIG. 5, this corresponds to the nth track 5 (the domain wall DW1 is trapped) and the (n + 3) th track 5. FIG. 5 shows the state of the pulse current at the stop time t _L , and the data region is stationary in the magnetic wire 5.

Here, in the (n + 2) th track 5, the position of the data area is ahead of the domain wall movement direction from the position of the domain wall between the data areas m + 1 and m + 2 and the domain wall between the data areas m + 2 and m + 3. It can be seen that there is a shift (shown as “shift” in FIG. 5). When the current is supplied to each track 5 from the state shown in FIG. 5 and the data area is moved by a distance of one data length, the domain wall between the data areas m + 1 and m + 2 is constricted in the n + 2th track 5. , And reaches the vicinity of the constricted portion 54, but when the supply of current is stopped, it quickly returns to the constricted portion 54 and stops. On the other hand, when the position of the data area is shifted backward in the domain wall movement direction, the movement due to the current is up to the front of the constricted portion 54, but even after the current supply is stopped, the movement is stopped after reaching the constricted portion 54. To do. That is, the displacement of the data area is corrected (not shown). As described above, each time the boundary of the domain wall, that is, the data area that is different between the stored data “0” and “1” reaches the constricted portion 54, the position shift of the data area is corrected. Therefore, if the tracks 5 are designed to have the same data length, the error in the movement distance of the data area is within a range that can be corrected by the constriction section 54. Therefore, malfunction does not occur even if the pulse current is not adjusted for each track 5. Can be suppressed. For example, as described above, two or more (four in this embodiment) tracks 5 to be reproduced simultaneously may be connected to the current supply unit 30 in parallel with the respective electrodes 52 and 53 in common. The position of the constricted portion 54 is not limited to the vicinity of the rear of the reproduction area 5 _RO shown in FIG. 5 but may be the vicinity of the front, and further provided at two or more places on the track 5 other than the vicinity of the reproduction area 5 _RO , for example. It's okay.

  Further, when the data area is set to move one data length by supplying current twice or more (2 clocks or more) as described above, the domain wall is easily trapped without intention of partial peeling or surface wrinkles. However, even if it exists in the middle portion of one data length in the magnetic thin wire (track) 5 or the like, the displacement of the data area is small due to the short movement distance of one clock, and it is more easily corrected by the constricted portion 54.

  The constricted portion 54 of the magnetic wire (track) 5 is preferably designed so that the domain wall is suitably trapped in a range of 20 to 98% of the cross-sectional area with respect to other regions of the magnetic wire 5. In the present embodiment, when forming a constriction in the width direction in a plan view as shown in FIG. 5, the width of the constricted portion 54 may be adjusted within the above range. Specifically, if the width of the constricted portion 54 is small with respect to the width of other regions (the constriction is small), the effect of trapping the domain wall becomes insufficient, and the displacement of the position of the data region is not corrected. There is a fear. On the other hand, if the width of the constricted portion 54 is excessively narrow (the constriction is large) with respect to the width of the other region, the domain wall is strongly fixed to the constricted portion 54, and the domain wall is moved from the constricted portion 54, that is, the data region is In order to move, it is necessary to increase the current (current density) supplied to the magnetic wire 5. In the case of forming the constriction in the width direction as shown in FIG. 5, it can be provided when forming the magnetic wire 5 in the manufacture of the magneto-optical disk 50. Alternatively, the constricted portion 54 may be formed by forming a recess only on one side in the width direction of the magnetic wire 5. Further, the constricted portion 54 may be constricted in the thickness direction. For example, the constricted portion 54 can be provided by partially shaving and denting the surface after the formation of the magnetic wire 5.

  Next, details of a method for simultaneously reproducing the magneto-optical disk by the magneto-optical recording medium reproducing apparatus according to the present invention, that is, the method of simultaneously detecting the magnetism of four adjacent tracks (magnetic thin wires) will be described with reference to FIGS. A description will be given with reference to FIG.

(Regeneration process: irradiation treatment)
In the optical system 10, the spot diameter is such that the laser light emitted from the laser irradiation device 11 includes the reproduction region 5 _RO (parallel reproduction region 50 _RO ) of the four magnetic thin wires 5 selected by the lens inside. In addition, since it includes various polarization components, it is transmitted through the incident polarization filter 13 in front of the magneto-optical disk 50 to obtain light of one polarization component (incident polarization). The spot diameter of the incident polarized light is adjusted according to the size of the parallel reproduction region 50 _RO , that is, the pitch of the tracks (magnetic thin wires) 5 and the number of parallel reproduction, but is preferably 0.2 to 100 μm. Incident polarized light is incident on the magnetic transfer film 8 on the parallel reproduction region 50 _RO of the magneto-optical disk 50, is transmitted therethrough, and is incident and reflected on each of the four magnetic thin wires 5 of the magneto-optical disk 50 at a predetermined incident angle. Then, the light is again transmitted through the magnetic transfer film 8 and emitted.

(Regeneration process: light detection process)
The outgoing polarized light reflected and emitted from each of the tracks (magnetic thin wires) 5 is discriminated whether the data recorded in the track 5 is “0” or “1” based on the direction of the polarized light. . As a method for detecting the direction of polarized light, a differential method applied to reproduction by a known magneto-optical method can be mentioned. In this embodiment, detection is performed as follows.

When the incident polarized light is transmitted downward through the magnetic transfer film 8, reflected by the magnetic wire 5, and transmitted through the magnetic transfer film 8 upward, the direction of the polarized light is rotated. Therefore, the light that has been transmitted through the magnetic transfer film 8 and exited (polarized light) is polarized light that has been rotated at an angle obtained by accumulating these rotation angles with respect to the incident polarized light. In this embodiment, since the data region in the reproducing region 5 _RO of the magnetic thin wire 5 in which one polarized light enters and exits and the region of the magnetic transfer film 8 immediately above it show the magnetization aligned in the upward or downward direction, The optical rotation angle (cumulative rotation angle) of the outgoing polarized light with respect to the incident polarized light can be expressed by + θk or −θk. That is, the outgoing polarized light reflected by the data area of the stored data “0” indicating the downward magnetization is rotated by the angle −θk, and the outgoing polarized light reflected by the data area of the stored data “1” indicating the upward magnetization is rotated by the angle + θk. Polarized light. The difference in optical rotation angle 2 | θk | is determined by the material of the magnetic wire 5, the material and film thickness of the magnetic transfer film 8, the wavelength and the incident angle of the laser beam, and is preferably 0.1 ° or more and large. As it will be (approaching 90 °), the magnetic detection accuracy improves as will be described later.

  The incident angle of the incident polarized light from the optical system 10 is inclined with respect to the magneto-optical disk 50 in FIGS. 1, 3 and 6, but this divides the optical paths of the incident polarized light and the outgoing polarized light. For example, it may be incident on the surface of the magneto-optical disk 50 perpendicularly (with an incident angle of 0 °). In particular, when the magnetic wire 5 is made of a perpendicular magnetic anisotropy material, the magneto-optic effect increases (2 | θk | increases) as the incident angle approaches 0 °, so that the detection accuracy can be improved. In the case of an incident angle of 0 °, a half mirror may be arranged to branch incident polarized light and outgoing polarized light (not shown).

All outgoing polarized light reflected and emitted from each track (magnetic thin wire) 5 reaches the outgoing polarizing filter 23. The output polarization filter 23 blocks specific polarized light, in this case, polarized light that has been rotated by an angle −θk with respect to incident polarized light, that is, light reflected by the downward magnetization data region, and transmits other light. Specifically, the outgoing polarization filter 23 transmits more polarized light having a larger difference in the direction with respect to the light to be shielded. If the polarized light has a difference of 90 °, in principle, 100% is transmitted. Therefore, 2 | θk | is large. The closer it is (closer to 90 °), the more the polarized light whose angle + θk is rotated with respect to the incident polarized light, that is, the light reflected in the data region of the upward magnetization is transmitted. Here, as shown in FIG. 6, the area (laser spot) irradiated with the incident polarized light on the surface of the magneto-optical disk 50 includes the data areas before and after the track 5 outside the parallel reproduction area 50 _RO , etc. Also includes light reflected in these data areas. Therefore, the light that has passed through the output polarization filter 23 includes light that has been reflected from the data region of the upward magnetization outside the parallel reproduction region 50 _RO . Therefore, a slit plate 24 having holes (slits) shaped to match the parallel reproduction region 50 _RO is disposed above the output polarization filter 23 to shield the outgoing polarized light reflected outside the parallel reproduction region 50 _RO . As a result, the imaging device 21 captures the light / dark pattern (bright, dark, bright, bright) of each data area of the nth to n + 3th four tracks 5 in the parallel reproduction area. Alternatively, the outgoing polarized light before passing through the outgoing polarizing filter 23 may be passed through the slit of the slit plate 24. Alternatively, the slit plate 24 may not be provided, and the imaging device 21 may be configured to capture only light incident on a predetermined area.

(Reproduction process: Data reproduction process)
In the imaging device 21, the imaging area is made to correspond to the parallel reproduction area 50 _RO , divided into four according to the number of tracks 5 reproduced in parallel, and the area where the light is imaged (detected) by photoelectric conversion is reproduced data “1”. The area that has not been imaged is recognized as reproduction data “0” and is signaled together with the position information of the area (track 5) or for each track 5. If 2 | θk | is large and the amount of polarized light transmitted through the output polarization filter 23 is large, the contrast of the bright / dark pattern imaged by the imaging device 21 becomes clearer, so that it is easy to discriminate even in a minutely divided imaging region. . When it is difficult to binarize data “0” and “1” by level slice processing, for example, the data length of the track 5 is shorter than the wavelength (half wavelength) of the laser beam emitted from the laser irradiation device 11. In this case, signal processing such as PRML (Partial Response Maximum Likelihood) may be performed. The obtained signal is output to the outside of the reproduction apparatus 1 and reproduced as information such as video and audio. In addition, the current supply unit 30 and the imaging device 21 are controlled by the control unit 40 so that the imaging of the light / dark pattern by the imaging device 21 is executed at the current stop time t _L in the pulse current.

  As described above, while detecting the magnetism, moving the data area in the track (magnetic thin wire) 5 and reproducing all the data stored in the track 5, the supply of the pulse current is stopped and the reproduction is performed. Step S2 is completed, and as shown in FIG. 7, a new track 5 is selected again in the selection step S1. In the present embodiment, the n + 4 to n + 7th tracks 5 following the nth to n + 3th tracks 5 that have been reproduced in the reproduction step S2 are selected according to the setting.

  As described above, according to the magneto-optical recording medium reproducing apparatus and the magneto-optical recording medium reproducing method according to the embodiment of the present invention, a plurality of data can be reproduced in parallel from one magneto-optical disk (magneto-optical recording medium). Therefore, it is suitable for reproducing high-definition image information or the like that requires a high-speed response. In this embodiment, one magneto-optical disk is built in the magneto-optical recording medium reproducing device, but two or more discs may be built corresponding to the capacity of information to be reproduced (illustrated). (Omitted). In this case, a means for replacing the magneto-optical disk 50 is further provided, the data recorded on the first magneto-optical disk 50 is reproduced, and then the position of the second magneto-optical disk 50 is changed to replace the second disk. The current supply unit 30 and the like are connected to the magneto-optical disk 50 and data reproduction is started. Alternatively, the optical system 10, the detection unit 20, the current supply unit 30 and the like may be provided in each of two or more magneto-optical disks 50, and these may be reproduced in parallel.

  The embodiments for carrying out the magneto-optical recording medium reproducing apparatus and the magneto-optical recording medium reproducing method of the present invention have been described above, but the present invention is not limited to these embodiments, and is shown in the claims. Various changes can be made within a range.

1 Playback device (magneto-optical recording medium playback device)
10 Optical system (irradiation means)
20 Detection unit (detection means)
30 Current supply section (current supply means)
40 Control unit (control means)
50 Magneto-optical disk (magneto-optical recording medium)
50 _RO parallel playback area 5 Magnetic wire (track)
5 _RO regeneration area (photomagnetic detection area)
8 Magnetic transfer film

Claims (6)

A plurality of magnetic thin wires formed by forming a magnetic material on a substrate in a thin line shape are provided as data recording areas, and each of the magnetic thin wires has binary data as one of two different directions of magnetization. A magneto-optical recording medium reproducing apparatus for reproducing data recorded on the magnetic thin line, comprising a magneto-optical recording medium continuously recorded in the direction of the thin line,
The surface of the magneto-optical recording medium is in close contact with a region including a magneto-optical detection region that is set in advance to each of the plurality of magnetic thin wires, and corresponds to the magnetization direction of the magnetic thin wire in the close contact region. A magnetic transfer film whose magnetization direction changes,
Control means for selecting two or more adjacent magnetic wires from the plurality of magnetic wires of the magneto-optical recording medium;
The two or more magnetic thin wires are connected to both ends of the plurality of magnetic thin wires of the magneto-optical recording medium, and one of the binary data is recorded in the magnetic thin wire and the other of the binary thin wires. Current supply means for supplying in the direction of the thin line a pulse current that intermittently moves the domain wall generated between the recorded data of
Irradiating means that transmits the polarized light in one direction to each of the magneto-optical detection regions of the two or more magnetic fine wires of the magneto-optical recording medium through the magnetic transfer film;
The direction of polarization of the light incident from the irradiation means, reflected from the two or more magnetic wires of the magneto-optical recording medium and transmitted through the magnetic transfer film is detected, and the two or more are detected from the direction of polarization of the light. Detecting means for reproducing data recorded on each of the magnetic thin wires in parallel,
The detection means reproduces data that has reached the magneto-optical detection area of the magnetic thin wire when the magnetic thin wire is stationary in intermittent movement of the domain wall in synchronization with the pulse current supplied by the current supply means. A magneto-optical recording medium reproducing apparatus. The detection means includes a polarizer that shields polarized light in a specific direction in light reflected from the two or more magnetic wires of the magneto-optical recording medium and transmitted through the magnetic transfer film, and transmitted through the polarizer. An imaging device that captures light at a stationary time in the intermittent movement of the domain wall in the magnetic wire; and
2. The magneto-optical recording according to claim 1, wherein a region imaged by the imaging device is divided according to each of the two or more magnetic thin wires, and the brightness of the light is reproduced as 0 or 1 data. Medium playback device.   In the magneto-optical recording medium, the substrate has a disk shape, the plurality of magnetic thin wires are concentrically formed on the substrate, and each of the magnetic thin wires has a shape lacking a part of a ring. The magneto-optical recording medium reproducing apparatus according to claim 1 or 2, characterized in that:   4. The magneto-optical recording medium reproducing apparatus according to claim 1, wherein the magneto-optical recording medium has a narrow portion in the vicinity of the magneto-optical detection region.   5. The magneto-optical recording medium reproducing apparatus according to claim 1, wherein the magnetic transfer film is made of bismuth-substituted magnetic garnet. A plurality of magnetic thin wires formed by forming a magnetic material on a substrate in a thin line shape are provided as data recording areas, and binary data is assigned to each of the magnetic thin wires as one of two different directions of magnetization. A magneto-optical recording medium reproducing method for reproducing data recorded on the magnetic thin line of a magneto-optical recording medium continuously recorded in a thin line direction,
The magnetization direction of the surface of the magneto-optical recording medium changes in accordance with the magnetization direction of the magnetic wire in the region in close contact with the region including the magneto-optical detection region positioned at each of the plurality of magnetic wires. A preparatory process for closely attaching the magnetic transfer film;
A selection step of selecting two or more adjacent magnetic wires from the plurality of magnetic wires of the magneto-optical recording medium;
Performing a reproduction step of reproducing data recorded on each of the two or more magnetic thin wires of the magneto-optical recording medium in parallel;
In the reproducing step, the two or more magnetic thin wires are generated between an area where one of the binary data is recorded and an area where the other binary data is recorded. A current supply process for supplying a pulse current for moving the domain wall intermittently in the direction of the thin line;
An irradiation process in which the polarized light in one direction is incident on the magneto-optical detection region of each of the two or more magnetic thin wires of the magneto-optical recording medium through the magnetic transfer film;
A light detection process for detecting the direction of polarization of light that has been incident in the irradiation process, reflected from the two or more magnetic wires of the magneto-optical recording medium, and transmitted through the magnetic transfer film;
In synchronization with the pulse current supplied in the current supply process from the direction of the polarization detected in the light detection process, the magneto-optics of the magnetic wire are stationary when the magnetic wall is intermittently moved in the magnetic wire. And a data reproducing process for reproducing the data that has reached the detection area.

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